Fix wrong imports

- "from _compatibility import ..." (not in circular imports)
- "from jedi import builtin" (one of circular imports)
- "api_classes = api.api_classes"
  ("from jedi import api_classes" is not supported)

jedi/parsing.py

@@ -15,11 +15,11 @@ within the statement. This lowers memory usage and cpu time and reduces the
 complexity of the ``Parser`` (there's another parser sitting inside
 ``Statement``, which produces ``Array`` and ``Call``).
 """
-from _compatibility import next, StringIO
 
 import tokenize
 import keyword
 
+from jedi._compatibility import next, StringIO
 from jedi import debug
 from jedi import common
 from jedi import parsing_representation as pr